One of the most effective ways of refuting the Protestant (particularly Calvinist) heresy of Eternal Security (aka Once Saved Always Saved) is to point out some examples of individuals in Scripture who at one point in their life were saved but then lost their salvation through grave sin (whether they repented or not is outside the scope of this brief article). The following list is by no means exhaustive, and I welcome any suggestions for other examples.
I have to credit Dave Armstrong (bookmark him!) with pointing this example out to me a while ago. 2 Chronicles 26:3-5, 16, 20-21 records the following about this man:
Uzziah was sixteen years old when he began to reign, and he reigned fifty-two years in Jerusalem. And he did what was right in the eyes of the LORD, according to all that his father Amaziah had done. He set himself to seek God in the days of Zechariah, who instructed him in the fear of God, and as long as he sought the LORD, God made him prosper.
But when he was strong, he grew proud, to his destruction. For he was unfaithful to the LORD his God and entered the temple of the LORD to burn incense on the altar of incense.
And Azariah the chief priest and all the priests looked at him, and behold, he was leprous in his forehead! And they rushed him out quickly, and he himself hurried to go out, because the LORD had struck him. And King Uzziah was a leper to the day of his death, and being a leper lived in a separate house, for he was excluded from the house of the LORD.
Clearly, there was a time when Uzziah was living in God’s favor, with no indication this was disingenuous. Yet, he “grew proud, to his destruction” to the point he was struck by God and never healed. (This is in contrast to those who have sinned and have healed after repenting.) This can only signify that Uzziah lost his salvation, and goes directly against the Protestant notion that good works will automatically flow. I’m sure there are similar situations for other OT Kings who at one point lived uprightly but then became corrupt.